1. Field of the Invention
This invention relates generally to joining components together to form a structural frame, and, more particularly, to joining a plurality of generally hollow frame members to form a space frame for a vehicle.
2. Discussion of Related Art
Structural components are joined to form structural frameworks for many purposes. Hollow structural components may be utilized in structural frames to decrease weight and simplify construction. Metal extrusions are often used because the cross-sectional shape of the extrusions can be designed to establish the desired shape and maximize the extrusion's strength while minimizing its weight. Structural frames which utilize hollow frame members have many uses. For example, U.S. Pat. No. 2,742,690 discloses a method of joining hollow components to form a window sash. International Patent Application No. PCT/DK84/00108 discloses a joint unit for joining hollow structural members. U.S. Pat. No. 4,709,241 discloses a satellite dish antenna frame. U.S. Pat. No. 4,076,432 discloses a corner construction for making furniture and the like.
One area where hollow frame members are used is in constructing space frames for motor vehicles. Because traditionally motor vehicles have been made of steel, the manufacturing methods have evolved into mature technologies. As the use of alternative materials, such as aluminum and resinous plastics, increases, alternative manufacturing processes must be developed. The inherent differences between steel and alternative materials, such as aluminum and plastics, prevent the direct application of all steel manufacturing technologies to such materials. Space frames technology is well suited for manufacturing motor vehicles using alternative materials.
Space frames permit flexibility for altering the design of the vehicle's body. In addition, the use of space frames results in lighter vehicle bodies which, in turn, may result in more fuel efficient vehicles. The points at which the frame members of a space frame are joined are typically referred to as nodes or node points. U.S. Pat. No. 4,660,345 discloses a vehicle space frame which utilizes castings to join the hollow structural members at the node points. The use of castings at the joints has several disadvantages. Castings are typically relatively expensive to produce and require expensive and specialized tooling to produce. Because of the complexity of the tooling and the complexity of designing the castings, long lead times and large financial investments are typically required if changes are to be made to the structural design of the space frame which uses castings. There is a need for a frame assembly method for joining hollow frame components which utilizes simple components for the joints, or frame assemblies, of the structure and which does not require the complex and expensive tooling and the long lead time associated with conventional assemblies.